Electrical contact means in wire springs



May 1954 H. v. ALEXANDERSSON 3,133,177

ELECTRICAL CQNTACT MEANS IN WIRE SPRINGS Filed Jan. 25, 1961 [iv VENTORHem/up Muoemm I44 :xn/wmmu fir roams/s United States Patent 3,133,177ELECTRICAL CONTACT MEANS IN WIRE SPRINGS Harald Valdemar Alexandersson,Lidingo, Sweden, as-

signor to Telefonaktiebolaget L M Ericsscn, Stockholm, Sweden, acorporation of Sweden Filed Jan. 25, 1961, Ser. No. 84,909 Claimspriority, application Sweden Feb. 10, 1960 6 Claims. (Cl. 200-166) Thereexists a number of constructions of electrical contact means for relaysand selectors used in telephone art, at which wire springs are usedinstead of the usual leaf springs. The constructions will thereby takeless room. In certain cases one makes use of the property of the wirespring of being able to bend a little sideways, perpendicularly to thenormal working direction, in order to obtain twin contact effect bymeans of only one pair of wire springs. The one contact spring then hasto be provided with an angle contact, the other contact spring makingcontact with both angle legs. Such a contact means is generally calledV-contact. It is however comparatively difiicult to manufacture such aV-contact and it is almost impossible to apply a suitable contactmaterial on the contact points in another way than galvanically, whichgives bad contact qualities.

The purpose of this invention is to obtain in a simple way reliableV-contacts on wire springs. This is achieved in such a way that the onecontact wire of a contact spring pair is provided with a tube consistingof contact material which tube is fixed on the contact wire in such away that one portion of the tube is placed outside the free end of thewire and that this portion along the side facing the other contact wirehas been given in cross section a V- shape suited for contact giving.

The invention will be further described with reference to the attacheddrawing. FIGS. 1 and 2 show a perspective view and an end view of aknown design of a V-contact means. FIGS. 3 and 4 show in correspondingviews the contact means proposed according to the invention.

At the perspective view, shown in FIG. 1, of a pair of wire contactsprings fastened at their back ends in the usual manner, the V-contactis formed by the lower contact wire. This is in its fore end, as alsoappears from FIG. 2, in which a front view of the fore ends of thesprings is shown, bent perpendicularly to the wire direction, and shapedas a little hook, in which the upper spring can make contact when thelower spring is brought upwards. The upper spring can thereby be bent alittle downwards against the V-contact as is shownin FIG. 1.

At the now proposed construction according to FIGS. 3 and 4, the uppercontact spring 1 is in front provided with a cylindrical tube 2 ofcontact material. The lower spring 3 is a little shorter than thespring 1. A piece of tube 4 is fastened on the fore end of the spring,for example by pressure or by welding. Part of the tube 4 is therebyplaced outside the free end of the wire. The tube is so long that thelower contact spring 3 and the projecting portion of the tube 4 togetherare equally long as the upper contact spring. The projecting portion ofthe tube 4 is, for example by stamping, so shaped that the upper sideadjoining the upper contact wire forms a piece 5 that is V-shaped incross section, which piece serves as contact point. When the lowerspring 3 is lifted by an operating member 6, the cylindrical, uppercontact tube will slide into the V-shaped groove 5 and makes contactagainst its both sides which form an angle with each other. Suitably theV-shaped portion 5 is bent up against the upper contact wire as is shownin FIG. 3, whereby the latter can be made straight.

By providing the two contact springs with tube-pieces of contactmaterial it is achieved that a sufliciently large quantity of suchmaterial is provided for the use intended for the springs. Thegeometrical dimensions of the springs will furthermore be such that thecontact means in its entirety, from the technical, manufacturing pointof view, is easy to make.

I claim:

1. A contact device for switching means, said device comprising a firstand a second springy wire, support means supporting said Wires inpositions in reference to each other in which said wires are movableinto engagement, and a sleeve made of contact material fitted upon anend of one of said wires lengthwise protruding therefrom, saidprotruding sleeve portion having a V-shaped configuration, the open sideof the V-shaped portion facing the other wire for receiving said otherwire in contact engagement at both inner surfaces of the V-shapedportion.

2. A contact device according to claim 1 wherein a cylindrical sleevemade of contact material is fitted upon one end of said other Wire, saidsleeve being engageable with the inner surfaces of said V-shaped sleeveportion.

3. A contact device according to claim 2 whereinsaid V-shaped sleeveportion is bent toward said other contact wire in reference to the axisof the wire on which said sleeve having the V-shaped portion is fitted.

4. An electric switching device comprising a first and a second springycontact wire, mounting means supporting said wires parallel to eachother in spaced-apart relationship, switch actuating means engaging oneof said wires to fiex one end thereof into contact engagement with theadjacent end of the other wire, a sleeve made of contact material fittedupon an end of one of said wires protruding from said end, saidprotruding sleeve portion having a V-shaped configuration, and acylindrical sleeve made of contact material fitted upon the adjacent endof the other wire, the open side of the V-shaped sleeve portion facingthe sleeve on the other wire for receiving said latter sleeve in contactengagement at both inner surfaces at said V shape.

5. A switching device according to claim 4 wherein said V-shaped portionis bent toward said other sleeve in reference to the axis of the wiremounting said sleeve-shaped portion.

6. A switching device according to claim 4 wherein the wire mounting thesleeve-shaped portion is shorter than the other wire, said protrudingV-shaped sleeve portion complementing the shorter wire substantially tothe length of the other wire.

References Cited in the file of this patent UNITED STATES PATENTS2,525,408 Graybill et al. Oct. 10, 1950 2,590,996 Miloche Apr. 1, 19522,866,046 Pandapas Dec. 23, 1958 2,965,739 Alexandersson Dec. 20, 1960FOREIGN PATENTS 592,127 France Apr. 24, 1925 545,664 Italy July 4, 1956163,785 Sweden July 1, 1958

1. A CONTACT DEVICE FOR SWITCHING MEANS, SAID DEVICE COMPRISING A FIRSTAND A SECOND SPRINGY WIRE, SUPPORT MEANS SUPPORTING SAID WIRES INPOSITIONS IN REFERENCE TO EACH OTHER IN WHICH SAID WIRES ARE MOVABLEINTO ENGAGEMENT, AND A SLEEVE MADE OF CONTACT MATERIAL FITTED UPON ANEND OF ONE OF SAID WIRES LENGTHWISE PROTRUDING THEREFROM, SAIDPROTRUDING SLEEVE PORTION HAVING A V-SHAPED CONFIGURATION, THE OPEN SIDEOF THE V-SHAPED PORTION FACING THE OTHER WIRE FOR RECEIVING SAID OTHERWIRE IN CONTACT ENGAGEMENT AT BOTH INNER SURFACES OF THE V-SHAPEDPORTION.